Radio communication networks are widely deployed to provide various communication services such as telephony, video, data, messaging, broadcasts, and so on. Such radio communication networks support communications for multiple wireless communication devices (sometimes referred to as User Equipments (UEs) herein) by sharing the available network resources. One example of such a network is the Universal Mobile Telecommunications System (UMTS), a third generation (3G) technology standardized by the 3rd Generation Partnership Project (3GPP). UMTS includes a definition for a Radio Access Network (RAN), referred to as UMTS Terrestrial Radio Access Network (UTRAN). The UMTS, which is the successor to Global System for Mobile Communications (GSM) technologies, supports various air interface standards, such as Wideband-Code Division Multiple Access (W-CDMA), Time Division-Code Division Multiple Access (TD-CDMA), and Time Division-Synchronous Code Division Multiple Access (TD-SCDMA). The UMTS also supports enhanced 3G data communications protocols, such as High Speed Packet Access (HSPA), which provides higher data transfer speeds and capacity to associated UMTS networks. As the demand for mobile broadband access continues to increase, research and development continue to advance the UMTS technologies not only to meet the growing demand for mobile broadband access, but to advance and enhance the user experience with mobile communications. For example, third-generation UMTS based on W-CDMA has been deployed in many places of the world. To ensure that this system remains competitive in the future, 3GPP began a project to define the long-term evolution of UMTS cellular technology. The specifications related to this effort are formally known as Evolved UMTS Terrestrial Radio Access (E-UTRA) and Evolved UMTS Terrestrial Radio Access Network (E-UTRAN), but are more commonly referred to by the name Long Term Evolution (LTE). More detailed descriptions of radio communication networks and systems can be found in literature, such as in Technical Specifications published by, e.g., the 3GPP.
PRACH is used for random access. According to the 3GPP Technical Specification TS 25.331 (v. 11.7.0), section 8.5.17 “PRACH selection” it is specified that the UE shall select the PRACH code randomly. After the selection of the PRACH index, then the UE proceeds with the signature selection based on the IE element Available Signature from “PRACH info” in case of proceeding with a RACH transmission or based on the IE element Available Signature from “PRACH preamble control parameters (for Enhanced Uplink)” in the case of E-DCH transmission. Thus, the PRACH selection is the selection of the physical channel and it follows the section 8.5.17 of 3GPP TS 25.331.
Further sections 8.5.73 and 8.5.74 of 3GPP TS 25.331 provide the parameters of how to access a specific set of PRACH configurations. If several PRACH configurations exist the selection is done for such candidate PRACH configurations. Further sections 10.3.6.55, 10.3.6.52, and 10.3.6.134 of 3GPP TS 25.331 specify a PRACH system information list, PRACH information and PRACH preamble control parameters extension list (for Enhanced Uplink), respectively.
Although the existing art with respect to the PRACH configuration selection provides many advantages, the inventors have realized that the existing PRACH configuration selection may be inadequate in future radio cell deployments.